In biology, histones are highly basic proteins abundant in lysine and arginine residues that are found in eukaryotic cell nuclei and in most Archaeal phyla. They act as spools around which DNA winds to create structural units called nucleosomes. Nucleosomes in turn are wrapped into 30-nanometer fibers that form tightly packed chromatin. Histones prevent DNA from becoming tangled and protect it from DNA damage. In addition, histones play important roles in gene regulation and DNA replication. Without histones, unwound DNA in chromosomes would be very long. For example, each human cell has about 1.8 meters of DNA if completely stretched out; however, when wound about histones, this length is reduced to about 90 micrometers (0.09 mm) of 30 nm diameter chromatin fibers.
The University of New South Wales (UNSW), also known as UNSW Sydney, is a public research university based in Sydney, New South Wales, Australia. It is one of the founding members of Group of Eight, a coalition of Australian research-intensive universities. It is ranked 19th in the 2024 QS World University Rankings.
Histone methyltransferases (HMT) are histone-modifying enzymes, that catalyze the transfer of one, two, or three methyl groups to lysine and arginine residues of histone proteins. The attachment of methyl groups occurs predominantly at specific lysine or arginine residues on histones H3 and H4. Two major types of histone methyltranferases exist, lysine-specific and arginine-specific. In both types of histone methyltransferases, S-Adenosyl methionine (SAM) serves as a cofactor and methyl donor group.
The genomic DNA of eukaryotes associates with histones to form chromatin. The level of chromatin compaction depends heavily on histone methylation and other post-translational modifications of histones. Histone methylation is a principal epigenetic modification of chromatin that determines gene expression, genomic stability, stem cell maturation, cell lineage development, genetic imprinting, DNA methylation, and cell mitosis.
Mark Sebastian Wainwright is an Australian chemical engineer and emeritus professor of the University of New South Wales, and institutional leader within the Australian academic and technological sectors. He served as seventh vice chancellor and president of the UNSW from 2004 to 2006. In 2004 he was appointed a member of the Order of Australia for services to chemical engineering as a researcher and academic, and to tertiary education. In 2007 he was awarded an honorary doctorate of science by the University of New South Wales. He was born 20 Oct.,1943.
Histone H4 is one of the five main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N-terminal tail, H4 is involved with the structure of the nucleosome of the 'beads on a string' organization. Histone proteins are highly post-translationally modified. Covalently bonded modifications include acetylation and methylation of the N-terminal tails. These modifications may alter expression of genes located on DNA associated with its parent histone octamer. Histone H4 is an important protein in the structure and function of chromatin, where its sequence variants and variable modification states are thought to play a role in the dynamic and long term regulation of genes.
Histone methylation is a process by which methyl groups are transferred to amino acids of histone proteins that make up nucleosomes, which the DNA double helix wraps around to form chromosomes. Methylation of histones can either increase or decrease transcription of genes, depending on which amino acids in the histones are methylated, and how many methyl groups are attached. Methylation events that weaken chemical attractions between histone tails and DNA increase transcription because they enable the DNA to uncoil from nucleosomes so that transcription factor proteins and RNA polymerase can access the DNA. This process is critical for the regulation of gene expression that allows different cells to express different genes.
There are several theatre and music venues at the University of New South Wales in Sydney, Australia.
Histone-modifying enzymes are enzymes involved in the modification of histone substrates after protein translation and affect cellular processes including gene expression. To safely store the eukaryotic genome, DNA is wrapped around four core histone proteins, which then join to form nucleosomes. These nucleosomes further fold together into highly condensed chromatin, which renders the organism's genetic material far less accessible to the factors required for gene transcription, DNA replication, recombination and repair. Subsequently, eukaryotic organisms have developed intricate mechanisms to overcome this repressive barrier imposed by the chromatin through histone modification, a type of post-translational modification which typically involves covalently attaching certain groups to histone residues. Once added to the histone, these groups elicit either a loose and open histone conformation, euchromatin, or a tight and closed histone conformation, heterochromatin. Euchromatin marks active transcription and gene expression, as the light packing of histones in this way allows entry for proteins involved in the transcription process. As such, the tightly packed heterochromatin marks the absence of current gene expression.
Histone deacetylase 4, also known as HDAC4, is a protein that in humans is encoded by the HDAC4 gene.
Protein IWS1 homolog also known as interacts with Spt6 (IWS1) is a protein that in humans is encoded by the IWS1 gene.
Marc R. Wilkins is an Australian scientist who is credited with the defining the concept of the proteome. Wilkins is a Professor in the School of Biotechnology and Biomolecular Sciences at the University of New South Wales, Sydney.
Edward Marcotte is a professor of biochemistry at The University of Texas at Austin, working in genetics, proteomics, and bioinformatics. Marcotte is an example of a computational biologist who also relies on experiments to validate bioinformatics-based predictions.
Bruce William Stillman, AO, FAA, FRS is a biochemist and cancer researcher who has served as the Director of Cold Spring Harbor Laboratory (CSHL) since 1994 and President since 2003. He also served as the Director of its NCI-designated Cancer Center for 25 years from 1992 to 2016. During his leadership, CSHL has been ranked as the No. 1 institution in molecular biology and genetics research by Thomson Reuters. Stillman's research focuses on how chromosomes are duplicated in human cells and in yeast Saccharomyces cerevisiae; the mechanisms that ensure accurate inheritance of genetic material from one generation to the next; and how missteps in this process lead to cancer. For his accomplishments, Stillman has received numerous awards, including the Alfred P. Sloan, Jr. Prize in 2004 and the 2010 Louisa Gross Horwitz Prize, both of which he shared with Thomas J. Kelly of Memorial Sloan-Kettering Cancer Center, as well as the 2019 Canada Gairdner International Award for biomedical research, which he shared with John Diffley.
SilentInformationRegulator (SIR) proteins are involved in regulating gene expression. SIR proteins organize heterochromatin near telomeres, ribosomal DNA (rDNA), and at silent loci including hidden mating type loci in yeast. The SIR family of genes encodes catalytic and non-catalytic proteins that are involved in de-acetylation of histone tails and the subsequent condensation of chromatin around a SIR protein scaffold. Some SIR family members are conserved from yeast to humans.
Liang Tong is a Chinese American biochemist, structural biologist, and the current chair of the Biological Sciences Department at Columbia University.
David Fenyö is a Swedish-American physicist and mass spectrometrist. He is currently professor in the Department of Biochemistry and Molecular Pharmacology at NYU Langone Medical Center. Fenyö's research focuses on the development of methods to identify, characterize and quantify proteins and in the integration of data from multiple modalities including mass spectrometry, sequencing and microscopy.
Thomas Jenuwein is a German scientist working in the fields of epigenetics, chromatin biology, gene regulation and genome function.
Katharine Arwen Michie is an Australian structural biologist, biochemist and physicist. In 2005 she was named a Fellow of the L'Oréal-UNESCO Awards for Women in Science and was also awarded a Marie Curie International Research Fellowship in January, 2006. Michie is currently in charge of the Structural Biology X-ray Facility, a part of the Mark Wainwright Analytical Centre, at the University of New South Wales, Sydney.
Set1 is a gene that codes for Histone-lysine N-methyltransferase and H3 lysine-4 specific proteins (H3K). Set1 proteins can also be referred to as COMPASS proteins. The first H3K4 methylase, Saccharomyces cerevisiae Set1/COMPASS, is highly conserved across a multitude of phylogenies. The histone methylation facilitated by Set1 is required for cell growth and transcription silencing through the repression of RNA polymerase II. The Set1C, COMPASS Complex, also aids in transcription elongation regulation and the maintenance of telomere length.
Lingjun Li is a Professor in the School of Pharmacy and Department of Chemistry at University of Wisconsin-Madison. She develops mass spectrometry based tools to study neuropeptides, peptide hormones and neurotransmitters.
